Methods for continuously controlling flux composition during manufacture of printed circuits
AssigneeCompaq Computer Corporation
InventorsDavid R. Bell, Paul V. Brownell
Life of this patent
Estimating the term…
Abstract
The invention provides a method that can be used online in a continuous printed circuit soldering process to measure and control the composition of soldering fluxes, in particular low-solids fluxes that utilize a solvent with a specific gravity close to the specific gravity of the flux composition. Samples of the flux are analyzed by ultra-violet absorption to determine solvent content and, based on this analysis, make up solvent is added to the flux composition to maintain a steady state composition.
Claims3
A method of determining and controlling the solvent concentration of a flux for soldering circuit boards, the method comprising:
- (a) sampling flux being used in a solder process for circuit boards, said flux comprising a solvent, said solvent having a specific gravity close to the flux specific gravity;
- (b) analyzing the sampled flux by ultra-violet absorbance to determine solvent content;
- (c) comparing analyzed solvent content with a control solvent content;
- (d) determining an amount of solvent to be added to the flux being used in the process so that solvent concentration of said flux is substantially equal to the control solvent content;
- and
- (e) adding the determined amount of solvent to the flux being used in the process.
Dependencies are inferred from the claim text.